לזכות ידידי אהובי ר' הערש יונתן בן ר' מרדכי אפרים לברכה והצלחה בכל מעשי ידיו
Our first guest in the Succah is Avraham. Avraham's middah was chesed.
There is a special category of chesed called "Toras Chesed". This is when one learns in order to teach others. The most pure type of chesed is that which mimics the chesed of Hashem in creating the world. When Hashem created the world there was giving without the attendant מכליא קרנא - consumption of the principal. He gave but lacked nothing. Usually when people give, they lose capital. That is why it is so hard to give. Imagine you could give a thousand dollars to tzedaka and immediately you would find a new thousand dollars in your pocket??
You'd give 50 thousand and you would find 50 thousand in your pocket. Then you'd say "What the heck" and give 10 mil. You look in your pocket and there is a good, clean check in your name for ten mil. [signed "HKB"H"]. But it doesn't quite work that way. We live in a world where it seems that מכליא קרנא - you lose the principal and get a mitzva in return. Many people love their capital more than they love mitzvos....
But when one teaches Torah it is a Toras Chesed - He gives and loses nothing in return. He only gains - ומתלמידי יותר מכולם.
That is most similar to the chesed Hashem displayed when creating the world. עולם חסד יבנה. Only giving without loss. That is the chesed of Avraham: אנכי מגן לך - The Targum translates מגן as חנם - for free. Hashem promised Avraham that his chesed would be free. No losses.
That is what we mean when we say ברוך אתה השם מגן אברהם - The foundation of ברכת אבות is this G-dly middah of מגן - Avraham performing chesed and not losing. Chesed is one of those mitzvos for which אוכלים פירותיהם בעולם הזה והקרן קיימת לעולם הבא - We eat the fruits in this world but the principal [of the reward] remains intact for the next.
Wonder of wonders.
[ עפ"י פחד יצחק ר"ה מאמר ב עיי"ש]